The class operated on the 1,435 mm (4 ft 8+1⁄2 in) Trans-Australian Railway.

Six were built by Perry Engineering, Gawler and 20 by Walkers Limited, Maryborough.

The Perry built locomotives received superheaters in 1943.

[1] Most survived until replaced by GM class diesel locomotives with the last withdrawn in September 1952.

[1] Media related to Commonwealth Railways KA class locomotives at Wikimedia Commons